May 4, 2009 - Technological Stasis in Sustainable Energy for the Home

One of the more regrettable aspects of the residential renewable energy industry is its conservatism. Renewable energy on the utility level and in industrial and transportation applications is profoundly innovative. Big corporate players and customers recognize the limitations of old technology and welcome the new. Not so with most of the value added resellers and installers that move much of the products aimed at residential markets. They're selling essentially the same kinds of systems they sold fifteen years ago. It's as if renewable energy were the industry of the past not the future.

I am determined to cover new technology in the book because if technology is not going forward there's simply no need for a new book. But at the same time I have to acknowledge that the successful introduction of new technology may not be rapid. Consumer markets are poor initial niches for almost any new technology because they are highly price sensitive and emerging technologies are nearly always costly simply because the volumes are so low in the beginning.

The manufacture of photovoltaic panels, which are the mainstay of residential renewable energy today, only achieved economies of scale because of the development of sizable commercial markets. But in the parallel case of fuel cells, which were supposed to play a major role in residential power, the commercial markets never materialized and the products remained priced way out of reach.

To a considerable degree that's still the case with wind. Relatively few homeowners have adopted wind generation, and so relatively few small wind turbines get sold. And the situation is exacerbated by the fact that the small wind turbine industry is so fragmented. With so many participants no one is doing any large percentage of the discouragingly low volume, and so manufacturing is inordinately costly.

So what emerging technologies are likely to play significant roles in the residential renewable systems of the midterm?

I'll venture some educated guesses.

The biggest deficiency in current systems is storage. The lead acid batteries in almost universal use today are bulky, short-lived, high maintenance, toxic, and somewhat dangerous to service. And they're not cheap. They also have low energy densities and thus don't provide a lot of runtime unless you choose to fill your basement with them.

So what will replace them?

That's not altogether certain. The most likely candidate as it stands today is the large format lithium ion battery which has a much smaller form factor for the same value of energy storage, is more robust, and is essentially zero maintenance. Current pricing for these devices is prohibitively high, but as the market for hybrid automobiles develops, large format lithium batteries will become commonplace and their prices will fall. Big lithium batteries have had safety issues in the past—they've been known to catch fire—but those problems are likely to be entirely solved before any mass rollout of lithium car batteries.

New designs of lead acid battery are also a possibility such as the Firefly and EffPower products. While these do not equal the performance of lithium ion, they appear to be cheaper to produce and home power is a price sensitive market.

Other battery chemistries represent much longer shots. Rechargeable air cathode batteries are a possibility, but not a strong possibility because of persistent problems energy efficiency and in product lifespan. Since this type of battery is also being researched for electric traction applications, and because such research is heavily subsidized, performance breakthroughs are certainly possible, and with them a spillover into other applications.

Another dark horse technology that may come to fruition is a specialized form of the ultra-capacitor. Current generation commercial ultra-caps are extremely expensive and have only a fraction of the total energy storage capacity of existing lead acid batteries, but some develops are now underway that could change. They're long shots at present, but if they pan out they could challenge the lead acid storage battery in residential markets.

Other technologies have been proposed for residential energy storage such as high velocity flywheels and regenerative fuels cells, but neither technology seems close to the point where it could be incorporated in a consumer product. For the time being advanced batteries appear to be the most likely successor technology.

In my next post I'll touch upon innovative power generation technologies.